DRB-induced premature termination of late adenovirus transcription

Exposure of HeLa cells to 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazde (DRB) late in the course of adenovirus 2 infection results in the inhibition of virus-specific RNA synthesis from all parts of the previously identified, very long (approximately 28 kilobases) late transcriptional unit, except for the first approximately 400-800 nucleotides. It is suggested that DRB acts not as an inhibitor of RNA chain initiation, but rather causes "premature" chain termination close to the promoter. A practical aspect of these findings may be that RNA sequences near promoter sites that are responsible for mRNA formation can be isolated from DRB-treated cells.